Narrated 'Abdullah bin 'Umar (ra): Allah's Messenger ﷺ entered Makkah through its upper part and he was riding his she-camel. Usama bin Zaid was his Companion-rider behind him (on the same she-camel). In his company were Bilal and 'Uthman bin Talha, who was one of the Al-Hajabah (who keep the key of the gate of the Ka'bah). When he made his she-camel kneel down in the Mosque (ie, Al-Masjid al-Haram), he ordered him (ie, 'Uthman) to bring the key of the Ka'bah. Then Allah's Messenger ﷺ entered the Ka'bah along with 'Usama bin Zaid, Bilal and 'Uthman bin Talha, and he stayed in it for a long period and then came out. The people rushed (to get in) and 'Abdullah bin 'Umar was the first to enter and he found Bilal standing behind the door. Ibn 'Umar asked Bilal, "Where did Allah's Messenger ﷺ offer the Salat (prayer)?" Bilal showed him the place where he ﷺ had offered Salat (prayer)'.Abdullah later on said, "I forgot to ask Bilal how many prostrations (ie, Rak'a) the Prophet offered".